Process of making rubber brushes



July 24, 192s.

R. M. WITHYCOMBE PROCESS 0F MAKING RUBBER BRUSHES OriginalA FiledKMarch31, 1925 Y strip stock in such a way as Patented July 24, 1928.

ROBERT MORSE WITHYCOMBE, OF SYDNEY, NEW SOUTH XALES,4 AUSTRALIA.

PROCESS OF MAKING RUBBER BRUSHES.

Original application led March 31, 1925, Serial No. 19,708. Divi-dedand. this application filed February 2, 1926.

This invention, which is divided out of my application No. 19,708 rfiledMarch 31, 1925, for bath spray brush, patented May 31, 1927, No.1,630,995, relates to a process of making rubber brushes and proposes anovel method of treating a filamentous rubber to produce brush heads forvarious purposes, characterized by the laminated arrangement of thestrip stock, producing a tufted congregation of the filaments at theworking end of the brush head, and a solid base portion at the other endwhich may be suitably attached to any device or handle. y

In its more specific adaptation, the process includes the step oftensioning the strip stock in the course of winding the brush,particularly when a filler is used in the center of the brush, so thatcertain layers of the iilamentous strip are drawn inward over thefiller, thus concealing the latter and giving to the brush a generalappearance of fullness which the amount of strip stock used would nototherwise justify, as well as imparting to a brush so formed, advantagesin function and use, some of which are referred to in the followingspecification.

In the drawings Figure 1 is a side elevation of a brush con structedaccording to the process of the present invention.

Figure 2 is a section taken along the line 2-2 of Figure 1.

Figure 3 is a section taken along the line 3 3 of Figure 2.

The brush head 1 is formed of a strip of rubber, slitted transversely atclose intervals along one longitudinal edge to form filaments, but uncutalong the other longitudinal edge. The present process, in its broadapplication consists in applying a coating of some suitable vulcanizingfluid or cement to the unslitted portion of the strip or rub ber, andthen rolling said strip into a close convoluted body, the unslittedportion forming a. solid base, having the vulcanizing coating betweenthe several lamin, and a filamentous portion or tuft, constituting theworking end of the brush. The process further contemplates the immersionof the brush head, thus formed, into boiling water or other suitableheating medium, to cause vulcanization of the base portion kof the brushinto an integral mass.

Serial No. 85,572.

A brush formed in this manner requires a considerable length of stripstock in the making, and is also quite heavy. Therefore in the interestof economy, lightness in weight, and other advantages it is sometimesdesirable to use a central filler or plug about which the rubber stripmay be wound. In its specific adaptation to this form of brush, theprocess includes the additional step of tensioning the rubber strip asit is wound around the filler, the tension being prefery ably graduatedfrom a maximum at the ben ginning of the winding operation to a minimumtoward the end of such operation. Tensioning the strip in this mannerhas the effect of drawing the inner filamentous la minae inwardly overthe filler as shown at 2 in Figure 3, and the progressive diminution ofthe tension causes the succeeding layers to be drawn in withprogressively less acuteness, as shown at 3 and 4 in the drawing, thefiller or plug being thereby concealed, and the brush being given anappearance of fullness, as though it were made in laminated form clearto the center.

In specific brushes, such as the one here shown in which the fillertakes the form of a perforated rose 5 adapted to be attached to a sourceof water flow 6, the inclined arrangement of the inner filaments, whichis due to the tensioning of the strip while the strip is being wound,produces novel advantageous effects which are more or less fully broughtout in my above mentioned U. S. Patent No. 1,630,995, the paths of thejets of liquid emanating from the rose being intersected by the innerlayer or layers of filaments so that the jets are transformed intonumerous films along the surfaces of the filaments, avoiding the directimpingement of the jets upon the surface to which the brush is appliedand consequent splashing,` and at the same time constantly flushing thefilamentous portion of the brush head; the liquid being supplied withoutwaste to the contacting surfaces of said filamentous portion and'saidsurface, where the cleansing action is taking place.

It is to be understood that while my process is illustrated in itsapplication to a specific form of brush, yet it is to be understood thatit is applicable to the manufacture of any brush whatsoever in which afilamentous rubber strip is incorporated into the brush by the processsubstantially as hereinbeere setforth.

Having described my invention what I claim as new and desire to secureby Letters Patent, iszl. The method of milking brushes of that typewhich include n spirully Wound' rubber strip formed With lilaments alongone of its longitudinal sides, Comprising Winding the strip upon itself,While at the-same time tensioning` the nonllamentous side with aprogressively varying tension.

2. he method ofl making brushes of that type which include a spirullyWound rubber strip formed with lilan'ients along one of its longitudinalsides, comprising winding the strip upon itself1 While at the saine timetensioning` the non-lilamentous side with a progressively decreasingtension.

3. The method of making a brush of that type which includes a rose witha strip of rubber formed With filaments along one of its longitudinalsides, disposed about the periphery of seid rose, comprising Winding thestrip spirally about said rose in a plurality of layers, While at thesume time, tensioning the non-filamentous side of Suid strip with eprogressively decreasing tension7 whereby the layers will progressivelyoverlie the rose, imparting fullness to the brush.

In testimony whereof my hand.

ROBERT MORSE XVTHYCOMBE.

have hereunto set

